[PATCH v4 0/1] Bluetooth: mediatek: add gpio pin to reset bt

[PATCH v4 0/1] Bluetooth: mediatek: add gpio pin to reset bt

[Zhangchao Zhang]

Reset Bluetooth using hardware pin via dts

Compared with the previously submitted version, the following
information are some specific revision histories

V3-->V4 modifications:
Modify dt binding format information and
the explanation text in the patch

V2-->V3 modifications:
-Changed the capitalization of co-developer names,
   using the correct capitalization of abbreviations and full
   name, and corrected obvious spelling errors.
-Add a revision history.
-Remove the "BT Driver" in the prefix.
-Add the bt-binding document, include inforamtion related to reset
   pin and compatibility matching.
-Add a comment before the schedule_delayed_work function call,
   although schedule_delayed_work is asynchronous, there is no risk.
   Even if it is not completed within 200ms, it will only postpone
   the subsequent probe and will not have any impact.
-Add a comment before the btmtk_reset_by_gpio function call,
   if the compatibility filed or pin cannot be found in the dts
   files, it can still reset bluetooth using software reset.

V2 modifications:
Modify gpio to GPIO, SW to software,
and fix other obvious spelling errors.

[PATCH v4 1/1] Bluetooth: mediatek: add gpio pin to reset bt

[Zhangchao Zhang]

Makes the platform Bluetooth to be reset by hardware pin,
it provides two methods to do it for mediatek controller,
and it has been tested locally many times and can reset normally.

When an exception occurs, resetting Bluetooth by hardware pin
is more stable than resetting Bluetooth by software.
If the corresponding pin is not found in dts,
bluetooth can also be reset successfully.

Co-developed: Hao Qin <hao.qin@mediatek.com>
Co-developed: Chris Lu <chris.lu@mediatek.com>
Co-developed: Jiande Lu <jiande.lu@mediatek.com>
Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
---
 drivers/bluetooth/btmtk.c | 69 +++++++++++++++++++++++++++++++++++++++
 drivers/bluetooth/btmtk.h |  5 +++
 2 files changed, 74 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 4390fd571dbd..3e5f3ca6f0d5 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -6,6 +6,8 @@
 #include <linux/firmware.h>
 #include <linux/usb.h>
 #include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -109,6 +111,65 @@ static void btmtk_coredump_notify(struct hci_dev *hdev, int state)
 	}
 }
 
+static void btmtk_reset_by_gpio_work(struct work_struct *work)
+{
+	struct btmtk_reset_gpio *reset_gpio_data =
+			container_of(work, struct btmtk_reset_gpio, reset_work.work);
+
+	gpio_direction_output(reset_gpio_data->gpio_number, 1);
+	kfree(reset_gpio_data);
+}
+
+static int btmtk_reset_by_gpio(struct hci_dev *hdev)
+{
+	struct btmtk_data *data = hci_get_priv(hdev);
+	struct btmtk_reset_gpio *reset_gpio_data;
+	struct device_node *node;
+	int reset_gpio_number;
+
+	node = of_find_compatible_node(NULL, NULL, "mediatek,usb-bluetooth");
+	if (node) {
+		reset_gpio_number = of_get_named_gpio(node, "reset-gpios", 0);
+		if (!gpio_is_valid(reset_gpio_number)) {
+			bt_dev_warn(hdev, "invalid reset GPIO, use software reset");
+			return -EINVAL;
+		}
+	} else {
+		bt_dev_warn(hdev, "no reset GPIO, use software reset");
+		return -ENODEV;
+	}
+
+	/* Toggle the hard reset line. The Mediatek device is going to
+	 * yank itself off the USB and then replug. The cleanup is handled
+	 * correctly on the way out (standard USB disconnect), and the new
+	 * device is detected cleanly and bound to the driver again like
+	 * it should be.
+	 */
+
+	if (test_and_set_bit(BTMTK_HW_RESET_ACTIVE, &data->flags)) {
+		bt_dev_err(hdev, "last reset failed? Not resetting again");
+		return 0;
+	}
+
+	reset_gpio_data = kzalloc(sizeof(*reset_gpio_data), GFP_KERNEL);
+	if (!reset_gpio_data)
+		return -ENOMEM;
+
+	INIT_DELAYED_WORK(&reset_gpio_data->reset_work, btmtk_reset_by_gpio_work);
+	reset_gpio_data->gpio_number = reset_gpio_number;
+
+	gpio_direction_output(reset_gpio_number, 0);
+
+	/* It requires 200ms for mtk bt chip to do reset,
+	 * although Schedule_delayed_work is asynchronous,
+	 * it is risk-free. If it is not completed in 200ms,
+	 * it will only postpone the next probe, which will
+	 * only make the probe run later. There is no other risk.
+	 */
+	schedule_delayed_work(&reset_gpio_data->reset_work, msecs_to_jiffies(200));
+	return 0;
+}
+
 void btmtk_fw_get_filename(char *buf, size_t size, u32 dev_id, u32 fw_ver,
 			   u32 fw_flavor)
 {
@@ -364,6 +425,14 @@ void btmtk_reset_sync(struct hci_dev *hdev)
 	struct btmtk_data *reset_work = hci_get_priv(hdev);
 	int err;
 
+	/* Toggle reset gpio if the platform provieds one,
+	 * if the compatibility field or pin cannot be found
+	 * in the dts files, it can still reset bluetooth using
+	 * software reset.
+	 */
+	err = btmtk_reset_by_gpio(hdev);
+	if (!err)
+		return;
 	hci_dev_lock(hdev);
 
 	err = hci_cmd_sync_queue(hdev, reset_work->reset_sync, NULL, NULL);
diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
index 5df7c3296624..8a265ce367d1 100644
--- a/drivers/bluetooth/btmtk.h
+++ b/drivers/bluetooth/btmtk.h
@@ -179,6 +179,11 @@ struct btmtk_data {
 	spinlock_t isorxlock;
 };
 
+struct btmtk_reset_gpio {
+	struct delayed_work reset_work;
+	int gpio_number;
+};
+
 typedef int (*wmt_cmd_sync_func_t)(struct hci_dev *,
 				   struct btmtk_hci_wmt_params *);
 
-- 
2.46.0

Re: [PATCH v4 0/1] Bluetooth: mediatek: add gpio pin to reset bt

[Krzysztof Kozlowski]

On 23/06/2025 12:23, Zhangchao Zhang wrote:
> Reset Bluetooth using hardware pin via dts
> 
> Compared with the previously submitted version, the following
> information are some specific revision histories
> 
> V3-->V4 modifications:
> Modify dt binding format information and

How? There is no binding, so what and how did you modify?

Best regards,
Krzysztof

Re: [PATCH v4 1/1] Bluetooth: mediatek: add gpio pin to reset bt

[Krzysztof Kozlowski]

On 23/06/2025 12:23, Zhangchao Zhang wrote:
> Makes the platform Bluetooth to be reset by hardware pin,
> it provides two methods to do it for mediatek controller,
> and it has been tested locally many times and can reset normally.
> 
> When an exception occurs, resetting Bluetooth by hardware pin
> is more stable than resetting Bluetooth by software.
> If the corresponding pin is not found in dts,
> bluetooth can also be reset successfully.
> 
> Co-developed: Hao Qin <hao.qin@mediatek.com>
> Co-developed: Chris Lu <chris.lu@mediatek.com>
> Co-developed: Jiande Lu <jiande.lu@mediatek.com>
> Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
> ---
>  drivers/bluetooth/btmtk.c | 69 +++++++++++++++++++++++++++++++++++++++
>  drivers/bluetooth/btmtk.h |  5 +++
>  2 files changed, 74 insertions(+)
> 
> diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> index 4390fd571dbd..3e5f3ca6f0d5 100644
> --- a/drivers/bluetooth/btmtk.c
> +++ b/drivers/bluetooth/btmtk.c
> @@ -6,6 +6,8 @@
>  #include <linux/firmware.h>
>  #include <linux/usb.h>
>  #include <linux/iopoll.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
>  #include <linux/unaligned.h>
>  
>  #include <net/bluetooth/bluetooth.h>
> @@ -109,6 +111,65 @@ static void btmtk_coredump_notify(struct hci_dev *hdev, int state)
>  	}
>  }
>  
> +static void btmtk_reset_by_gpio_work(struct work_struct *work)
> +{
> +	struct btmtk_reset_gpio *reset_gpio_data =
> +			container_of(work, struct btmtk_reset_gpio, reset_work.work);
> +
> +	gpio_direction_output(reset_gpio_data->gpio_number, 1);
> +	kfree(reset_gpio_data);
> +}
> +
> +static int btmtk_reset_by_gpio(struct hci_dev *hdev)
> +{
> +	struct btmtk_data *data = hci_get_priv(hdev);
> +	struct btmtk_reset_gpio *reset_gpio_data;
> +	struct device_node *node;
> +	int reset_gpio_number;
> +
> +	node = of_find_compatible_node(NULL, NULL, "mediatek,usb-bluetooth");


Can you finally respond to the comments you got weeks ago at v1?

NAK and I will keep NAKing your patches because total disregard to
review is not going to make this patch accepted.


Best regards,
Krzysztof

Re: [PATCH v4 1/1] Bluetooth: mediatek: add gpio pin to reset bt

[Luiz Augusto von Dentz]

Hi,

On Mon, Jun 23, 2025 at 7:55 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On 23/06/2025 12:23, Zhangchao Zhang wrote:
> > Makes the platform Bluetooth to be reset by hardware pin,
> > it provides two methods to do it for mediatek controller,
> > and it has been tested locally many times and can reset normally.
> >
> > When an exception occurs, resetting Bluetooth by hardware pin
> > is more stable than resetting Bluetooth by software.
> > If the corresponding pin is not found in dts,
> > bluetooth can also be reset successfully.
> >
> > Co-developed: Hao Qin <hao.qin@mediatek.com>
> > Co-developed: Chris Lu <chris.lu@mediatek.com>
> > Co-developed: Jiande Lu <jiande.lu@mediatek.com>
> > Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@mediatek.com>
> > ---
> >  drivers/bluetooth/btmtk.c | 69 +++++++++++++++++++++++++++++++++++++++
> >  drivers/bluetooth/btmtk.h |  5 +++
> >  2 files changed, 74 insertions(+)
> >
> > diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
> > index 4390fd571dbd..3e5f3ca6f0d5 100644
> > --- a/drivers/bluetooth/btmtk.c
> > +++ b/drivers/bluetooth/btmtk.c
> > @@ -6,6 +6,8 @@
> >  #include <linux/firmware.h>
> >  #include <linux/usb.h>
> >  #include <linux/iopoll.h>
> > +#include <linux/of.h>
> > +#include <linux/of_gpio.h>
> >  #include <linux/unaligned.h>
> >
> >  #include <net/bluetooth/bluetooth.h>
> > @@ -109,6 +111,65 @@ static void btmtk_coredump_notify(struct hci_dev *hdev, int state)
> >       }
> >  }
> >
> > +static void btmtk_reset_by_gpio_work(struct work_struct *work)
> > +{
> > +     struct btmtk_reset_gpio *reset_gpio_data =
> > +                     container_of(work, struct btmtk_reset_gpio, reset_work.work);
> > +
> > +     gpio_direction_output(reset_gpio_data->gpio_number, 1);
> > +     kfree(reset_gpio_data);
> > +}
> > +
> > +static int btmtk_reset_by_gpio(struct hci_dev *hdev)
> > +{
> > +     struct btmtk_data *data = hci_get_priv(hdev);
> > +     struct btmtk_reset_gpio *reset_gpio_data;
> > +     struct device_node *node;
> > +     int reset_gpio_number;
> > +
> > +     node = of_find_compatible_node(NULL, NULL, "mediatek,usb-bluetooth");
>
>
> Can you finally respond to the comments you got weeks ago at v1?
>
> NAK and I will keep NAKing your patches because total disregard to
> review is not going to make this patch accepted.

Can someone at mediatek respond to Krzysztof, he is the maintainer of
device tree, so he has the authority to NAK patches so you guys better
start addressing his requests.

-- 
Luiz Augusto von Dentz